Pigment.



our sans rgnr are.

JOSEPH G. HEOKMAN, OF AVALON PENNSYLVANIA, ASSIGNOR OF ONE-HALF TOWILLIAM J.

GILMORE, OF PITTSBURG, PENNSYLVANIA.

PIGMENT.

Specification of Letters Patent.

Patented May 5, 1908.

Application filed June 12, ,1907. Serial No. 378,655.

To all whom it may concern:

Be it known that I, JosEPH O HEOKMAN, a resident of Avalon, in thecounty of Allegheny and State of Pennsylvania, have invented a new anduseful Improvement in Pigments; and I do hereby declare the following tobe a full, clear, and exact description thereof.

My invention relates to pigments.

The object of my invention is to provide a pigment of high color andbrilliancy obtained from a waste product heretofore accounted as of nocommercialvalue:

' My invention consists, generally stated, in a pigmentproduced bytreating flue dust from iron or steel furnaces. with sulfuric -acid andthen calcining same.

As the apparatus involved in the manufacture of my improved )igment isof a form commonly employed I have not deemed it necessary to accompanymy description with drawings.

In the operation of a blast furnace for makin iron great quantitiesofflue dust or dirt co lect inthe hot blast stove which have to beremoved from time to time to keep the furnace in proper working order.This flue dust is composed of silica, oxid of iron, carbon, alumina,lime, &c., in varying proportions, depending upon the character of theiron or lime stone and coke employed. This flue dust has heretofore beenconsidered as a waste product andthrown aside as refuse. In themanufacture of my improved pigment I take this flue dust and mix it withproper proportions ofsulfuric or other suitable To be more exact,

mineral acid and water. I may introduce into a suitable vat or reservoirone part flue dust, one fifth to one part sulfuric acid and one fifth toone part water, and after thoroughly mixing the same the mixture isallowed tostand for a suitable length of time to give the sulfuric acidsuflicient time to thoroughly act on the iron and thus convert it intocompounds which, through subsequent stages of the process, to wit:'calcination, are readily converted into oXid of iron. The reactionbetween the iron and the sulfuric acid gives sulfate of iron ,which inits crystalline form is well known as copperas. In my process, however,the sulfate of iron formed is in a hydrated form and is merely anintermediary product which has no resemblance to the commercial articleknown as cop eras.

After the mixture has stood for the length of time required, say, fromtwelve to thirtysix hours, the mixture will be in the form of asemi-fluid or pasty mass through the chemical reactions taking place.Thismixture I then introduce into a suitable muffle or rewhich is veryrich in iron maid of a very bril-.

liant red in coloring and very strong in tinting capacity. By increasingthe proportion of the sulfuric acid up toa certam point a high color andstrength is obtained. This increase m sulfuricacid, however, dependsupon the amount of metallic iron contained in the flue dust from whichthe pigment is made. The igment so produced may then be mixed wit 1.suitable 011s, turpentine, &c., to produce paint adapted for Iron orwood work. Furthermore, the pigment may also be employed for coloringmany other lines of manufacture.

By my invention I make use of a waste product and give it a highcommercial value, while at the sametime the pigment obtained therefromhas a high color and has great strength as the present establishedstandard at greatly reduced cost. In addition to this blast furnace fluedust I may also employ the flue dust which collects in the dust catchersof open hearth furnaces and which consists rimarily of iron ore and limedust. This flue dust may be treated in the same manner as above setforth to produce the pigment.

What I claim is:

1. As a new product'of manufacture a pigment formed from furnace fluedust by treating same with a mineral acid and calcining the same.

2. As a new product of manufacture, a pig- JOSEPH C. HEOKMAN.

Witnesses:

ROBERT C. TOTTEN, RoBT. D. TOTTEN.

